diff --git a/.github/workflows/tests-mailman.yaml b/.github/workflows/tests-mailman.yaml
index 2243bcce4..1e1b6d6b7 100644
--- a/.github/workflows/tests-mailman.yaml
+++ b/.github/workflows/tests-mailman.yaml
@@ -6,6 +6,9 @@ on:
   push:
     branches:
       - master
+  pull_request:
+    branches:
+      - master
 
 jobs:
   run_tox:
diff --git a/tools/testing/fetch_mailman.sh b/tools/testing/fetch_mailman.sh
index 18135e786..d5a6aa74d 100755
--- a/tools/testing/fetch_mailman.sh
+++ b/tools/testing/fetch_mailman.sh
@@ -19,14 +19,11 @@ cd $MAILMAN_PATH
 # git checkout tags/$MAILMAN_VERSION
 
 # NOTE(vytas): Patch tox.ini to introduce a new Falcon environment.
-# TODO(vytas): Remove the shim pinning importlib-resources once
-#   https://gitlab.com/mailman/mailman/-/merge_requests/1130 is merged upstream.
 cat <<EOT >> tox.ini
 
 [testenv:falcon-nocov]
 basepython = python3.8
 commands_pre =
-    pip install "importlib-resources < 6.0"
     pip uninstall -y falcon
     pip install $FALCON_ROOT
 EOT